WEF Executive Chairman Klaus Schwab attributed the gains to improvements in U.S. financial markets and public institutions, two of 12 "pillars" on which the organization judges national competitiveness.

"While the economy is getting back on track, the deleveraging process in the banking sector continues to show positive effects on the stability and efficiency of the country's financial markets, improving from 31st three years ago to 10th this year in that pillar. At the same time, the assessment of public institutions is slightly more positive, which is a hopeful outcome after a number of years of weakening confidence in this area," Schwab said in the report.

He added that pre-existing structural factors continued to boost the U.S. economy's productivity.

"U.S. companies are highly sophisticated and innovative, supported by an excellent university system that collaborates admirably with the business sector in R&D. Combined with flexible labor markets and the scale opportunities afforded by the sheer size of its domestic economy—the largest in the world by far—these qualities continue to make the United States very competitive," he said.

Switzerland and Singapore retained their positions as the world's most competitive economies, coming in first and second, respectively.

According to WEF, Switzerland's most notable strengths were innovation, labor market efficiency and the sophistication of its business sector.

"Switzerland's top-notch scientific research institutions, along with other factors, make the country a top innovator. Productivity is further enhanced by a business sector that offers excellent on-the-job-training opportunities, both citizens and private companies that are proactive at adapting the latest technologies and labor markets that balance employee protection with business efficiency. Moreover, public institutions in Switzerland are among the most effective and transparent in the world," Schwab said.

At the other extreme, Chad was rated the least competitive country in the world, followed by Guinea and Burundi.